Response Analysis Of Gear Meshing Self-excited Vibration

Gear mechanism is one of the most widely used transmission mechanisms in various institutions,which used in aerospace,large heavy equipment,automobile and other industries.With the arrival of Industry 4.0 and the development of manufacturing technology,the requirements for gear transmission systems are steadily heading toward high-speed,heavy-load,and light-weight applications.However,with the increasing load of transmission system,the enlarging transmission power and the declining mass,a series of problems such as aggravated structural vibration and serious gear wear will occur.Therefore,the research of gear vibration and noise,which is aimed at improving the gear box design level and smooth operation,has an important theoretical significance and engineering value.In this paper,the traditional single-stage spur gear reducer is taken as the research object.The research is focused on the time-varying meshing stiffness,transmission error of spur gears,the internal gear excitation simulation,bearing equivalent stiffness calculation,gearbox vibration simulation and test signal processing.The main research contents are as follows:(1)For the time-varying meshing stiffness of gears,three solving methods are proposed:(1)ISO empirical formula method,(2)potential energy method(3)finite element method based on Romax software.Considering the calculation time and accuracy of the three calculation methods,it is the finite element calculation that is adopted in this paper owing to its high popularity and accuracy.(2)Aiming at gear error excitation,a two-degree-of-freedom gear simplified model is used to establish the gear box static model.The gear equations of motion are founded.After the process of Matlab software,the static transmission error curve of gear pair is solved by finite difference method.At the same time,the influences on static transmission error caused by different speed,torque and other factors are analyzed.Combined with the stiffness excitation in the previous chapter,the internal excitation of spur gear is obtained.(3)Based on the finite element model of the rolling bearing,which is established by APDL,its static analysis is conducted.Besides,the bearing radial stiffness is calculated.Due to the periodic changing of the bearing stiffness,it is necessary to use the equivalent stiffness to obtaina valid value.The equivalent spring can be used to simulate the changes of bearing force and displacement.(4)The finite element software is used to construct the gear system model including gear bearing and gearbox.According to the solution of the internal gear excitation,a simulated vibration of gearbox is conducted by modal superposition method.Based on the vibration experiment platform,the vibration test of the gearbox is carried out to obtain the time-domain vibration curve of the measuring point on the box surface.Its test signal is processed by FFT transform method.Finally,compared the results of test and simulation,the accuracy of research method can be verified.